Searchlights ever able to display lunar?

[train2]

This is generic seachlight signal question. I posted it here because a lot of the UP and esp. SP had searchlights. Perhaps someone might know the answer.

Has anyone ever seen a searchlight signal with anything other than red/yellow/green colors? It is my understanding that they have a three color roundlet. Could the 3 colors ever be configured to display lunar (white) as one of the three colors? Did any of the western roads like SP use white for a signal or is restricting on those roads red/yellow or red/red/yellow?

What colors did the lower head of seachlight have available? If it was a single train length siding, esp. a non-signaled siding all the lower head would have needed was red/yellow. Did such a roundlet exist?

If you can think of any better forum to post please advise.

[TB Diamond]

The lunar aspect relayed the information that the train or engine whose movement was subject to the signal was to pass the signal at restricted speed.

[ljeppson]

A double searchlight array (one on top of the other) near my boyhood home on the Rio Grande often displayed a red over lunar (which I was told was a "call on" whatever that means). I always thought red over lunar was sort of a low grade green, based on my observations. During the early UP takeover days this signal displayed a yellow over lunar aspect. This signal has since been replaced. There are no longer any lunar aspect signals in the Salt Lake area now as far as I know.

[train2]

Call on is a signal very much like restricting. It is given at a place where a train would have to enter an occupied siding or main. A great example would be to add helpers to the rear of a train standing on the main. A call on givens them a very low speed movement into a occupied track.

On the Northeast Corridor they use call ons to allow trains to enter busy stations behind another train at the platform. Once the head train loads and departs the second slides into place at the platform.

[train2]

Good info, so you saw a searchlight that had white in the color roundlet. That is good to know.

My guess is the roundlet could not be designed with 4 colors to give R/Y/G/L.

[slchub]

We use a lunar all the time on the Shafter and the Provo Subs (Salt Lake City hub) (Approach Restricting and Restricting). You'll see Approach Restricting coming into the SLC Depot from the south at 13th South and Restricting headed into the depot track at 8th South. They'll use searchlight type lunars on the bottom portion of a double mast signal. I've not seen a lunar displayed in a single searchlight type signal on the former WP, DRGW or SP. But that is not to say they are not out there.

[roee]

Has anyone ever seen a searchlight signal with anything other than red/yellow/green colors? It is my understanding that they have a three color roundlet. Could the 3 colors ever be configured to display lunar (white) as one of the three colors? Did any of the western roads like SP use white for a signal or is restricting on those roads red/yellow or red/red/yellow?

Searchlights only have space for 3 roundells. Typically it is G, R, Y, in that order, with Red in the middle. Some times they do have lunar, so Y, R, L. If used, typically on B heads. For areas that have non-controlled sidings that get a Red/Lunar, typically the bottom head will be a single color, which is the same for sidings and approach signals that will only display a yellow on the bottom head. Why put a relay on the mast if it is only going to show one color. Searchlight signals are relays and therefore have tests that are required that isn't required on a colorlight signal.

[GN 599]

We (BNSF) run on 78 miles of former SP main. There are a few searchlights that give a ''lunar''. They are only in two locations, and they either give lunar "restricting'' or red "stop".

[NV290]

Searchlights only have space for 3 roundells. Typically it is G, R, Y, in that order, with Red in the middle. Some times they do have lunar, so Y, R, L. If used, typically on B heads..

Correct. The fail safe design would make it impossible to display more then three aspects. So red will always be in the middle with another color having to be substituted for Lunar.

[train2]

Explain if you can, why red was needed in the middle? Was it weighted to fall to the middle color as a fail safe?

Anyone got any photos of the inside of one of these?

[NV290]

Explain if you can, why red was needed in the middle? Was it weighted to fall to the middle color as a fail safe?

Anyone got any photos of the inside of one of these?

Red is in the middle because of like you said, in the fail safe mode, the spectacle arm is weighted to fail with the middle aspect displayed. So the middle aspect is always red.

I don't have any photo's handy. But alot of times i see pictures when people are selling them on ebay.

Here is a link to a picture. You can see the signal in the red position. If you look closeley, you can see the shape of the spectacle arm.

http://images.google.com/imgres?imgurl= ... N%26um%3D1

[slchub]

Found another lunar on the SLC Hub this morning at CPC782 (9th West in SLC) from the Lynndyl Sub to the SLC sub on MT2 eastward. Yellow over lunar headed eastbound. We (Amtrak #6) were headed to Wyoming due to track maintenance on the normal route.

[Engineer Spike]

To add to the fail safe nature of the red being in the middle, if power is removed, it centers on red. The polarity of the power to the signals is set one way for green, and reversed for yellow. It has been my experience that if a signal needs to show a yellow and green aspect, and it also needs to display restricting, then a flashing red is used instead. An example of the would be at a crossover between 2 main tracks. Now say that there is also a yard lead in this controlled point as well. This could be signaled in two ways.
In all cases a movement continuing on the same track would get either a green or red on top. A movement crossing over to the other main would get a green or yellow on the second head. The display of the signal for the yard lead is where the options come in. This is based on the signal practices of the railroad. In this case, since the second head can't display 4 aspects, The second head would have to display a flashing red for restricting indication. The other option would be to have a third head. This bottom head would be configured to display lunar for restricting.
Now we will go back to the topic of the centering to red fail safe design. There was a rule in the Canadian Railway Operating Rules (CROR) that a leaning signal mast has to be considered as a improperly displayed signal. This is because it might not center back to red. Depending on which way the signal is leaning, a yellow or green aspect may be displayed, even though it should default to red.

[NV290]

In all cases a movement continuing on the same track would get either a green or red on top. A movement crossing over to the other main would get a green or yellow on the second head. The display of the signal for the yard lead is where the options come in. This is based on the signal practices of the railroad. In this case, since the second head can't display 4 aspects, The second head would have to display a flashing red for restricting indication. The other option would be to have a third head. This bottom head would be configured to display lunar for restricting.

It ultimatley would depend on what rulebook you were working under. Under NORAC, a three light color light signal with a steady bottom yellow is a Restricting. So while some railroads may have to go with flashing red, others can utilize the normal colors.

[Engineer Spike]

I was commenting on the use of a lunar for restricting. This post was about western signaling. NORAC and CROR use a yellow on the bottom. A searchlight signal would not be able to display 4 colors in one signal head.